Process for smoking foodstuffs



Dec. 16, 1941. c. THON 2,266,131

PROCESS FOR SMOKING FOODSTUFFS Filed Oct. 4, 1938 Patented Dec. 16, 1-941 1 ,PBOCESS FOB SMOKING FOODSTUFFS Christian Thon, Oslo, Norway Application October 4, 1938, Serial No. 233,302

. In Germany October 6, 1937 3 Claims. (01. sis-229) The present invention relates to a process 'for the smoking or food products by replacing the air contained in the cells or pores of the goods by smoke, by evacuation of the smoking cham- -ber in which the goods to be treated are placed and introducing the smoke into the chamber. In

accordance with the invention, the smoke gases are introduced into the smoking chamber at a pressure which is approximately the same as the pressure residing in the smoking chamber at any moment. It has previously been suggested to evacuate the smoking chamber before the smoking is started, but according to these previous suggestions the smoke is introduced into the evacuated smoking chamber at a pressure of one or more atmospheres, whereby a sudden expansion of the smoke gases takes place, accompanied by a condensation in part of the said gases. The condensation products will be deposited on the goods and give the same an undesirable appearance and taste. By the present invention this expansion and condensation are avoided and an even and thorough penetration of the smoke in the goods obtained, the goods being, as a rule, ready smoked when the pressure in the smoking chamber has reached the atmospheric pressure. Thus the smoking process according to the invention results in a quicker smoking through of the products wherefore a comparatively great smoking capacity will be obtained even with a comparatively, small apparatus.

The smoke conveniently is produced during the smoking process at approximately the same pressure as the gradually increasing pressure in the smoking chamber. In order to achieve this, the chamber wherein the smoke is developed may be evacuated before the smoking is started. This evacuation may be carried out jointlywith the evacuation of the smoking chamber, or, when the smoke producing chamber has a small volume as compared with the smoking chamber, by bringing the smoke producing chamber into communication with the already evacuated smoking chamber.

An apparatus for carrying out the process according to the invention conveniently may be so constructed that the smoke producing chamber is arranged within, or in open connection with, the smoking chamber, in such a manner that the smoke producing chamber is evacuated simultaneously with the smoking chamber, but it is also possible to connect the smoke producing chamber to the smoking chamber by means of a conduit provided with a stop valve or the like.

In this case the smoke producing chamber may be evacuated separately or by being put in connection with the already evacuated smoking chamber. The smoke production is regulated during the smoking by means of an adjustable air inlet valve in connection with the smoke producing chamber, in such a manner that at any time onlythe quantity of air. required for the production of smoke of the desired-pressure is introduced. Thus, only the quantity of smoke required for the carrying out of the process is produced, whereby it is economically possible to use the best and purest qualities of fuel, for instance aromatic woods, thereby giving the goods any desired aroma and flavour.

The smoke temperature conveniently is adjusted by means of a cooling jack'et enclosing the connection conduit between the smoke producing chamber and the smoking chamber and, if desired also the smoke producing chamber and/or the smoking chamber.

The accompanying drawing illustrates schematically an example of an apparatus for carrying out'the process according to the invention. Figure 1 is a vertical longitudinal section through an apparatus wherein the smoking chamber is in communication with the smoke producing chamber, and Figure 2 a vertical cross section of the smoking chamber.

In the figures, I is the smoking chamber consisting of a cylindrical container which is closed at one end and at the other end provided with a door 2, with a quick closing arrangement. The interior of the smoking chamber is provided with laths, shelves, nets or the like for the placing of the goods to be treated, 3 isa water jacket enclosing the cylindrical wall of the smoking chamber and 4 an insulation, covering the end walls of the chamber. to a ventilator for the withdrawal of unused smoke from the chamber after completed treatment, and at 6 the chamber is connected to a vacuum pump 1 for the evacuation of the chamber before the smoking process is started. Further, the chamber may be provided with an air and ash pan ll. This container also is enclosed At 5 the chamber is connected by a water cooling jacket l8 and is provided with observation windows l9. In the lower portion of the container is an electric filament 20 for the ignition of the fuel, and the air supply for the smoke production is controlled by means of the air inlet valve 2|. In order to prevent the flames from entering the chamber I or the conduit l2 the combustion portion of the chamber I 3 suitably is covered by a fine mesh grid 22. The chamber also may be provided with a safety valve 23. I

The treatment suitably is carried out by introducing fuel in predetermined-quantities into the smoke producing chamber and inserting the grid 22. The cover l5 thereafter is applied and the goods to be treated are placed in the chamber I,

whereafter the door 2 is closed and the vacuum pump I started. When the desired vacuum is obtained a current is passed through the filament until ignition temperature of the fuel is reached, whereupon the valve 2| is slightly opened. By means of the valve 2| the smoke production is so controlled that the pressure in the chamber I is gradually increased until atmospheric pressure is reached, at which time the smoking as a rule is completed, all pores and cells of the goods then being completely filled with smoke of atmospheric pressure.

What I claim is:

1. A method for smoking food products comprising the steps of evacuating an enclosure containing both the products to be smoked and the smoke producing fuel, igniting the fuel, gradually admitting a combustion supporting gas to the enclosure until atmospheric pressure is reached, whereby the smoke is produced at approximately the pressure existing in the pores and cells of the vacuum treated products and penetrates said pores and cells as the ambient pressure within the enclosure is increased, and whereby deleterious condensation of products of combustion in and upon said food products is eliminated.

2. A method for smoking food products comprising the steps of evacuating an enclosure containing both the products to be smoked and the smoke producing fuel, igniting the fuel, gradually admitting a combustion supporting gas to the enclosure in the vicinity of said igniting fuel, whereby the smoke is produced at approximately the pressure existing in the pores and cells of the vacuum treated products .and penetrates said pores and cells as the ambient pressure within the enclosure is increased, and whereby deleterious condensation of products of combustion in and upon said food products is eliminated.

3. A method for smoking food products comprising the steps of evacuating a smoke generating chamber and a chamber containing the products to be smoked both to substantially the same degree, producing smoke gases in said generating chamber at approximately said degree of sub-atmospheric pressure, providing free intercommunication between said chambers, and gradually supplying combustion air to said generating chamber at a rate suillcient to maintain combustion of the smoke producing fuel, whereby the smoke is produced at approximately the pressure existing in the pores and cells of the vacuum treated products and penetrates said pores and cells as the ambient pressure within the enclosure is increased, and whereby deleterious condensation of products of combustion in and upon said food products is eliminated.

CHRISTIAN THON. 

